ESP8266 Community Forum

I'm using ESP8266 just for WiFi connectivity and Atmega32U4 for reading various sensors. One of sensors is microphone that is preamplified and connected to analog input of AtMega32U4.

Without ESP8266 connected it works just fine, it reads very small changes on analog input when there is silence. But as soon as I connect ESP it starts jumping around. My ESP sends data every 2 seconds and I can see that analog value jumps every 2 seconds.

Tried powering ESP8266 from separate power supply and works just fine.

ESP8266 is powered from the same 5V rail trough LM1117 3.3V. Tried to put lot of decoupling capacitors right to ESP8266 and it helps a bit but still my reading are jumping arounds. Even tried choke in series with EPS8266 but didn't help.

Any ideas to fix this without using two separate adapters to power Atmega32U4 and ESP8266 ?

One common problem people have is that they don't join all the earths. Just in case you hav'nt done that .

Sure, all modules share the same ground.

I managed to reduce noise by using additional LM1117 3.3V for powering sound module. I can still see noise on analog input but it is 2-3x reduced.
But this is still not enough good because I need to detect even small noise changes.

Just wondering if you use the traditional capacitors on each regulator?